A Cam With Kick
Dustin Lyall, Somewhere in Canada: I need some help with a cam recommendation. I'm looking for a cam to put into my '71 Nova. The drivetrain is a 350 engine with a four-speed and a tall rear gear-around 3.08 or so. I'm aiming for a good daily-driver engine that has a moderate kick to it. I'm looking for a cam with an LCA of 114 with a duration of no more than 220 to 224 degrees at 0.050 and a valve lift of around 0.460 to 0.490 inch. I have been looking at Lunati, Comp Cams, and a few others and haven't found anything that matches up the LCA, duration, and valve-lift numbers.
I have an SBC 350 (from a third-gen F-body) in my '69 Beaumont; I'm guessing the compression ratio is approximately 10:1 based on the pistons we used with stock heads. It also has an Edelbrock Performer RPM intake, headers, a GMPP LT4 Hot cam, and a 700-R4 with a 2,000-rpm stall. I want to hit 400 hp and torque, but streetability and durability are much more important. I don't mind a rumbly cam and have access to 94-octane pump gas.
I am very disappointed with the heads; I have bent a pushrod twice, and the valves just don't sound good. The guy at the machine shop referred to them as 416s, but I've never heard of that model. I was thinking of stepping up to aftermarket heads like Dart's Iron Eagles or the Edelbrock Performer RPM, but they are pricey. What size combustion chambers and runners would work best with this combo? What about valve and spring size and rocker ratio?
Jeff Smith: First, let's address your cylinder-head question, and then we'll get into the cam specs. You mentioned your machine shop told you the heads are 416s. This is typical hot-rodder cylinder-head shorthand that refers to the last three numbers of the cylinder-head casting number. Assuming we have the right head, the full number is 14014416, which is a cast-iron 305 head used on small-block 305 engines from 1980 through 1986 that came with 58cc combustion chambers and rather small 1.84/1.50-inch valves. With these small-chamber heads, we can see why you have 10:1 compression, but whatever the small gain with compression you enjoy is more than offset by the rather weak airflow potential of these heads.